Cisco Systems OL-11497-03 manual Interface Configuration Mode, Subinterface Configuration Mode

Chapter 3 Installing the Router

Cisco IOS User Interface

Global Configuration Mode

Global configuration commands apply to features that affect the system as a whole, rather than just one protocol or interface. Use the configure terminal privileged EXEC command to enter global configuration mode. Commands to enable a particular routing or bridging function are global configuration commands.

Interface Configuration Mode

Many features are enabled on a per-interface basis. Interface configuration commands modify the operation of an interface, such as Ethernet, FDDI, or serial port. Interface configuration commands always follow an interface global configuration command, which defines the interface type.

For details on interface configuration commands that affect general interface parameters, such as bandwidth or clock rate, refer to the “Interface Commands” chapter in the Configuration Fundamentals Command Reference. For protocol-specific commands, see the appropriate Cisco IOS software command reference.

Subinterface Configuration Mode

You can configure multiple virtual interfaces (called subinterfaces) on a single physical interface. Subinterfaces appear to be distinct physical interfaces to the various protocols. For detailed information on how to configure subinterfaces, see the appropriate module for a specific protocol in the Cisco IOS software documentation.

ROM Monitor Mode

If your router does not find a valid system image, or if you interrupt the boot sequence, the system might enter read-only memory (ROM) monitor mode. From ROM monitor mode, you can boot the system or perform diagnostic tests. You also can enter ROM monitor mode by entering the reload EXEC command and then pressing the Break key during the first 60 seconds of startup.

	Cisco 12006 and Cisco 12406 Router Installation and Configuration Guide
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